An Automated Teller Machine (ATM) is an example of a processing device to which access must be carefully controlled. Such machines are often the target of fraudsters due to the large amounts of money that they hold and the confidential nature of data supplied thereto, both in the form of customer entered Personal Identification Numbers and in the form of bank account details. However, ATMs must be accessible by engineers as they require regular maintenance, replacement of parts and updates to system software. Such maintenance is often carried out by “field engineers”, who generally travel to the site of the ATMs for this purpose.
Access to ATMs is often controlled though the use of access tokens such as flex disks or key fobs which carry a machine readable identity in the form of a computer readable memory, a bar code, RFID tag or the like. In order to gain access to the interior workings of the machine, a field engineer would allow a data reader on the ATM to read data from his or her assigned access token and, providing that the access token was valid and within its set license period, the field engineer would be granted access to the ATM. In prior art devices, the license period was held on the access token in the form of a length of time (usually in months) and an expiry date.
This system was only secure as long as the access token remained in the care of the field engineer. In order to improve security, companies deploying ATMs began to require that a password also be entered. Under such a system, the access token must be valid, within its license period and a valid password would have to be supplied before a field engineer is granted access to the ATM.
In some existing systems, two types of access token were issued. A trusted group (for example, employees of the ATM company) were provided with an access token allowing ‘Master’ level access and a less trusted group (for example, third party maintenance engineers) were provided with an access token allowing ‘Basic’ level access. Master level access would allow more complex and security critical tasks to be carried out by the engineer, such as updating system software and inserting new components, whereas basic level access would allow access to the interior for basic maintenance.